Field
Embodiments of the disclosure relate generally to the field of structures for interattachment of materials and components with significantly differing coefficients of thermal expansion (CTE) and more particularly to a composite structure with constituents having a graduated CTE for connection of two structures with vastly different CTE and a method for creation of the graded CTE composite structure.
Description of the Related Art
The need for higher capability, weight efficient, and long lasting extreme environment structures has necessitated the use of higher capability advanced extreme environment materials (e.g., without limitation, ceramic matrix composites, carbon-carbon composites, refractory metals/alloys/intermetallics, cermets, and intermetallic compounds). Such advanced materials possess vastly different CTEs compared to common structural alloys. Additionally, they may be less ductile. Incorporation of such advanced materials into the design of an extreme environment structure inevitably may require them to be attached, at some point, to common structural alloys with much higher CTE and ductility. When exposed to the intended extreme environments, significantly high thermal stresses and strains may be developed, which may lead to undesirable results. This has been a critical issue, which has either completely restricted the use of these advanced structural materials or has resulted in costs skyrocketing, whether it be for weight penalties or increase in complexity of designs to allow for attachment to available structural alloys. Attaching members with dramatically different CTEs for use in high and low temperature applications is an extremely challenging task. Existing solutions (which are usually not feasible if members have dramatically different CTEs) mainly involve complicated mechanical fastening devices, which may involve complex mechanisms and/or complex designs to allow for relative movement between members with different CTEs when the assembly is heated or cooled. Existing solutions tend to be non-rigid due to the fact that they may be inherently flexible to allow relative movement and they may have features that are not favorable for use in typical high temperature applications, such as engines, turbines, and vehicle leading edges.
It is therefore desirable to provide a structure that can be used to attach members with vastly different CTE to produce an assembly that can be heated or cooled without introducing significant thermal stresses or strains.
It is further desirable to provide a system that does not rely on complicated mechanisms and complex designs to allow relative deformation during heating or cooling, allowing for a substantially rigid solution tailored to inherently accommodate for the wide CTE mismatch encountered in extreme environment applications such as engines, turbines and vehicle leading edge subsytems.